The present invention relates to a power transmitting system for a hybrid motor vehicle using an internal combustion engine and an electric motor.
Recently, there has been developed the hybrid vehicle which is driven by the engine and the motor from the point of view of low pollution and resource economy.
In the hybrid motor vehicle, two motors which are selectively used as a power source and as a power generator are mounted, thereby increasing energy efficiency and driving performance.
Japanese Patent Application Laid Open 9-46821 discloses a hybrid motor vehicle in which a power distribution mechanism using a differential distributor such as a differential gear is used for distributing a part of engine power for a power generator so that the power by power generator is used for driving a motor so as to drive the motor vehicle.
Japanese Patent Application Laid Open 9-100853 discloses a hybrid motor vehicle where a planetary gear is provided for distributing engine power to a power generator.
However, in the above described prior arts, a great part of the driving power at low vehicle speed is relied on the motor. Accordingly, it is necessary to mount a large motor having a large output, and to provide a power generator having a large power in order to maintain a constant running performance. As a result, the cost for manufacturing the motor vehicle increases.
Furthermore, in the case that the rotation speed of the output shaft of an engine changes over a control range for controlling the motor speed, it is difficult to properly control the engine and the motor in response to requested driving force, only by distributing the power of the engine to the power generator.
An object of the present invention is to provide a power transmitting system for a hybrid motor vehicle which may ensure necessary driving force and increase the energy efficiency by using two motors, and may properly control the engine and the motors in response to requested driving force.
According to the present invention, there is provided a power transmitting system for a hybrid motor vehicle comprising, an engine, a planetary gear having a sun gear, a carrier rotatably supporting a plurality of pinions each of which engages with the sun gear, a ring gear engaging with the pinions, a first motor connected to an output shaft of the engine and the sun gear of the planetary gear, and capable of using as a driving source and as a power generator, a second motor connected to the ring gear and capable of using as a driving source and as a power generator, and a transmission connected between the carrier of the planetary gear and an axle of the motor vehicle.
The present invention further provides a power transmitting system for a hybrid motor vehicle comprising, an engine, a planetary gear having a sun gear, a carrier rotatably supporting a plurality of pinions each of which engages with the sun gear, a ring gear engaging with the pinions, a first motor connected to an output shaft of the engine and the ring gear of the planetary gear, and capable of using as a driving source and as a power generator, a second motor connected to the sun gear and capable of using as a driving source and as a power generator, and a transmission connected between the carrier of the planetary gear and an axle of the motor vehicle.
The present invention still further provides a power transmitting system for a hybrid motor vehicle comprising, an engine, a planetary gear having a sun gear, a carrier rotatably supporting a plurality of pinions each of which engages with the sun gear, a ring gear engaging with the pinions, a first motor connected to an output shaft of the engine and the ring gear of the planetary gear, and capable of using as a driving source and as a power generator, a second motor connected to the carrier and capable of using as a driving source and as a power generator, and a transmission connected between the carrier of the planetary gear and an axle of the motor vehicle.
A clutch is provided for engaging two members selected from the sun gear, ring gear and carrier of the planetary gear.
The transmission may be a continuously variable belt-drive automatic transmission.
These and other objects and features of the present invention will become more apparent from the following detailed description with reference to the accompanying drawings.